I spent some time trying to figure out why our commit emails contained
differences even for binary files like MSWord documents. Eventually
I realized that 'svnlook diff' looks at the svn:mime-type keywords
to determine whether to explicitly show the diff.

This small fact is not documented in the Subversion book, so here's
a tiny patch to fix that.

These files had no MIME type because they were imported from a CVS
repository (note to Karl: does svn2cvs apply the same MIME type
heuristic that 'svn add' does?)

Also, I wrote a simple script that slurps in "mime.types" files (in
Apache httpd's format) and then scans a working hierarchy, setting
svn:mime-type for all files with recognized suffixes.. might be
useful for the SVN utilities project?